From: Matthew Wilcox <willy@infradead.org>
To: David Laight <david.laight.linux@gmail.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>,
ebiederm@xmission.com, oleg@redhat.com, brauner@kernel.org,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 6/6] pid: drop irq disablement around pidmap_lock
Date: Sat, 1 Feb 2025 22:00:06 +0000 [thread overview]
Message-ID: <Z56ZZpmAbRCIeI7D@casper.infradead.org> (raw)
In-Reply-To: <20250201215105.55c0319a@pumpkin>
On Sat, Feb 01, 2025 at 09:51:05PM +0000, David Laight wrote:
> I'm not sure what you mean.
> Disabling interrupts isn't as cheap as it ought to be, but probably isn't
> that bad.
Time it. You'll see.
> > So while this is indeed a tradeoff, as I understand the sane default
> > is to *not* disable interrupts unless necessary.
>
> I bet to differ.
You're wrong. It is utterly standard to take spinlocks without
disabling IRQs. We do it all over the kernel. If you think that needs
to change, then make your case, don't throw a driveby review.
And I don't mean by arguing. Make a change, measure the difference.
next prev parent reply other threads:[~2025-02-01 22:00 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-01 16:31 [PATCH v3 0/6] reduce tasklist_lock hold time on exit and do some Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 1/6] exit: perform add_device_randomness() without tasklist_lock Mateusz Guzik
2025-02-03 17:51 ` Oleg Nesterov
2025-02-03 17:55 ` Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 2/6] exit: hoist get_pid() in release_task() outside of tasklist_lock Mateusz Guzik
2025-02-03 19:27 ` Liam R. Howlett
2025-02-03 19:35 ` Mateusz Guzik
2025-02-03 20:13 ` Liam R. Howlett
2025-02-03 20:22 ` Mateusz Guzik
2025-02-03 20:28 ` Liam R. Howlett
2025-02-04 1:51 ` Andrew Morton
2025-02-01 16:31 ` [PATCH v3 3/6] exit: postpone tty_kref_put() until after tasklist_lock is dropped Mateusz Guzik
2025-02-03 18:06 ` Oleg Nesterov
2025-02-03 19:33 ` Mateusz Guzik
2025-02-04 11:22 ` Oleg Nesterov
2025-02-04 12:12 ` Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 4/6] pid: sprinkle tasklist_lock asserts Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 5/6] pid: perform free_pid() calls outside of tasklist_lock Mateusz Guzik
2025-02-03 18:49 ` Oleg Nesterov
2025-02-03 19:31 ` Mateusz Guzik
2025-02-03 20:02 ` Oleg Nesterov
2025-02-01 16:31 ` [PATCH v3 6/6] pid: drop irq disablement around pidmap_lock Mateusz Guzik
2025-02-01 17:42 ` Oleg Nesterov
2025-02-01 17:45 ` Oleg Nesterov
2025-02-01 18:19 ` David Laight
2025-02-01 18:42 ` Mateusz Guzik
2025-02-01 21:51 ` David Laight
2025-02-01 22:00 ` Matthew Wilcox [this message]
2025-02-02 13:55 ` David Laight
2025-02-02 19:34 ` Mateusz Guzik
2025-02-02 20:44 ` David Laight
2025-02-02 22:06 ` Matthew Wilcox
2025-02-03 17:47 ` [PATCH v3 0/6] reduce tasklist_lock hold time on exit and do some Oleg Nesterov
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